Containerize PhoneNumberUtil instance for Phone rule

[alganet]

Similar to d8e31db (commit that containerized iso code dbs), but this time for PhoneNumberUtil.

This makes the optional dependency testable.

PhoneNumberUtil doesn't have a public constructor, so a factory was declared instead.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.14%. Comparing base (d8e31db) to head (b728098).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1643      +/-   ##
============================================
+ Coverage     99.00%   99.14%   +0.13%     
  Complexity      962      962              
============================================
  Files           197      197              
  Lines          2214     2215       +1     
============================================
+ Hits           2192     2196       +4     
+ Misses           22       19       -3     

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[Copilot]

Pull request overview

This PR containerizes the PhoneNumberUtil instance for the Phone validator by registering it in the dependency injection container, making the optional dependency testable. This change aligns with the previous containerization of ISO code databases (commit d8e31db).

Changes:

• Added PhoneNumberUtil factory registration in the container with getInstance() call
• Changed Phone validator to check for PhoneNumberUtil availability via container instead of class_exists()
• Updated error message to match the pattern used by other validators
• Added comprehensive tests for both missing dependencies (PhoneNumberUtil and Countries)

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/ContainerRegistry.php	Registers PhoneNumberUtil factory in the default container definitions
src/Validators/Phone.php	Updates dependency checking to use container instead of class_exists(), removes unused import
tests/unit/Validators/PhoneTest.php	Adds tests for missing PhoneNumberUtil and missing Countries dependencies, renames existing test for clarity

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